The present invention relates generally to engine oil sensors.
Automatically monitoring the quality of oil in an engine alerts the owners or operators in a timely fashion when maintenance should be performed as dictated by the actual condition of the oil. Performing maintenance when it is actually required is preferred over following a predetermined, one-size-fits-all schedule that might be too long or too short for any given vehicle, depending on the way the vehicle is driven. If too long a period elapses between maintenance, a vehicle can be damaged. On the other hand, conducting maintenance when it is not needed is wasteful both in terms of labor and in terms of natural resources. For example, if a vehicle doesn""t require an oil change but nevertheless receives one, oil is in effect wasted.
Accordingly, oil condition sensors, having a generally cylindrical shape, have been provided for measuring various parameters of lubricating oil, and to generate warning signals when maintenance is due as indicated by the condition of the oil. Among the parameters that are typically measured are oil temperature, contamination, and degradation. In a light vehicle, these sensors are usually mounted in the oil pan beneath the engine. The sensitivity of these sensors relies heavily on the surface area of the sensor. Thus, as the surface area increases, the signal strength increases.
The present invention recognizes that in order to increase the surface area, either the length of the sensor or the diameter of the sensor is increased. Because of sensor size considerations, it is often the length of the oil condition sensor that is increased instead of the diameter of the sensor. Unfortunately, in an oil pan, the length of the sensor is constrained by the depth of the pan. As such, the present invention understands that in deep oil pans the length of the sensor can be increased without problem, but in shallow oil pans increasing the length of the sensor can be problematic.
The present invention has recognized these prior art drawbacks, and has provided the below-disclosed solutions to one or more of the prior art deficiencies.
An oil sensor includes a first level sensing tube, and a common tube that surrounds the level sensing tube. A second level sensing tube surrounds the common tube. The second level sensing tube is electrically connected to the first level sensing tube and the common tube is separated from the first and second level sensing tubes.
In a preferred embodiment, the oil sensor includes a coupling/plug that is installed in the end of the first level sensing tube. A condition sensing tube is disposed around the coupling/plug. Accordingly, the coupling/plug insulates the condition sensing tube from the first level sensing tube. Preferably, tubes are concentric.
In a preferred embodiment, the sensor includes plural spacers that are installed between the first level sensing tube and the common tube and between the common tube and the second level sensing tube. Preferably, the sensor is disposed in a relatively shallow oil pan. Moreover, in a preferred embodiment, the sensor is connected to a control module. The control module receives signals from the sensor that represent the level and condition of oil in the oil pan. The control module is also connected to a warning device. The warning device receives a signal from the control module when the level of the oil or the condition of the oil falls outside a predetermined operating range.
In another aspect of the present invention, a vehicle oil lubricating system includes an engine and an oil pan. An oil sensor is disposed in the oil pan. In this aspect of the present invention, the oil sensor includes two level sensing tubes for sensing a level of oil in the oil pan and a condition sensing tube for sensing a condition of oil in the oil pan.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: